With the iPhone 5s, Apple debuted its first non-A-series chip within an iOS device. Called the M7, it was a motion co-processor that tracked your movements while drawing minimal power, making the iPhone 5s the first smartphone that could passively do what an activity band like the FitBit can do: track all your steps during the day.

We haven’t heard much about whether or not we can expect an update to the M7 in the iPhone 6, but according to the latest leak, we can. An Apple chip internally code-named Phosphorus is now believed to replace the M7 in the iPhone 6./